Such heat exchangers have the advantage that the heat-emitting surface area in a heating element (or the heat-absorbing surface area in an absorber of a heat pump) is substantially increased in comparison with a heat exchanger which includes only the steel wall or hollow member. The effect of the heat baffle plate increases as the heat flow in the member increases. This heat flow depends on one hand on the specific heat conductivity and on the other hand on the cross section of the member.
In a conventional heat exchanger of the above-mentioned type, the heat baffle plate is made of steel. The use of a steel baffle plate evolved because the manufacture of a heat-conducting connection can be created very inexpensively by directly welding together the heat baffle plate and the steel member. Of course, the efficiency of heat baffle plates of steel is limited because of the relatively poor heat conductivity of this material, and because for weight and cost reasons the heat baffle plate can only be of a moderate thickness and heat conduction is proportional to the sheet-metal plate thickness.
A basic purpose of the invention is to provide a heat exchanger of the above-mentioned type in which the efficiency of the heat baffle plate is substantially increased for a given plate thickness. In a further development of the basic thought of the invention, advantageous heat-conducting connections between the steel member and the heat baffle plate are provided.